The South American expedition led by Dr. Alexander Hamilton Rice, who is accompanied by Mrs. Rice, formerly Mrs. George D. Widener of Philadelphia, is equipped to make an aerial survey of the Amazon and Orinoco Rivers, according to Sherman M. Fairchild, President of the Fairchild Aerial Camera Corporation, who made public yesterday the text of a letter sent to him by Dr. Rice before he sailed for Brazil. Dr. and Mrs. Rice were reported safe at Manaos, where recent political disturbances interrupted navigation of the Amazon.
Dr. Rice planned to do a great deal of aerial survey work and took with him a large steel boat and two flying boats. The flying boats were equipped with Fairchild six-mile cameras of the type used by Captain A. W. Stevens to make the first high-altitude photographs of Dayton, Ohio. Captain Stevens, at a height of six miles, photographrd [sic] on one plate the entire City of Dayton, covering nineteen square miles. He sailed from New York recently to join Dr. Rice's expedition, which will try to discover the source of the Orinoco. In his letter to Mr. Fairchild, Dr. Rice said:
"The advantages of aerial photography as an auxiliary to the ordinary procedures of exploratory and geographical surveys are the much enlarged area of territory that may be gone over in a given time, the consequently greatly increased amount of map detail possible, and the covering of districts otherwise inaccessible either by reason of physical obstacles or the hostility of the inhabitants.
"On the ordinary traverse surveys such as even a well-equipped and efficiently manned expedition is capable of carrying out, very little correct and exact detail of the surrounding country will be acquired beyond that contiguous to the narrow route followed. The employment of aerial photography graphically changes this limitation of local knowledge into an opportunity of almost limitless general information.
"One of the most difficult things in cartography is to generalize, to show the leading characteristics of land formation and general physical features of a country without giving undue prominence to comparatively unimportant details.
"Those regions where the natives are so hostile or the physical obstacles so great as to effectually bar progress or ingress to domain which it is desired to penetrate, the airplane passes over easily and quickly, affording opportunity to acquire by aerial photography whatever may be desirable or neceasary."